Spark plug wire problem?
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 3,615
Likes: 1
From: New Lenox IL
Spark plug wire problem?
I just changed my spark plugs yesterday and my car is running terrible now. It was acting up before but not like this. It just needed some time to warm up. Now, the car is kinda shaking and not getting full power on WOT. Almost sounds like it wants to die cause its flooded at the idle.
I checked the wires, and they seem to be all on right. I'm thinking I may have accidentally switched two of the wires up. How can I tell? Following the wires on the driver side is a PITRA.
I checked the wires, and they seem to be all on right. I'm thinking I may have accidentally switched two of the wires up. How can I tell? Following the wires on the driver side is a PITRA.
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: Spark plug wire problem? (Lord Odin)
I had to wring out each wire one by one with a DMM till I found the two that were switched.
Just pull a wire off a spark plug and pull the other end from the dist and check resistance. If any pair are swapped those two wires will show infinite impedence.
Just pull a wire off a spark plug and pull the other end from the dist and check resistance. If any pair are swapped those two wires will show infinite impedence.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Spark plug wire problem? (Lord Odin)
I just changed my spark plugs yesterday and my car is running terrible now. It was acting up before but not like this. It just needed some time to warm up. Now, the car is kinda shaking and not getting full power on WOT. Almost sounds like it wants to die cause its flooded at the idle.
I checked the wires, and they seem to be all on right. I'm thinking I may have accidentally switched two of the wires up. How can I tell? Following the wires on the driver side is a PITRA.
I checked the wires, and they seem to be all on right. I'm thinking I may have accidentally switched two of the wires up. How can I tell? Following the wires on the driver side is a PITRA.
The only other things I can think of is that you cracked one of the plugs during installation and/or the plug gaps weren't set properly.
Jake
[Modified by JAKE, 3:55 PM 5/4/2004]
Drifting
Joined: Nov 2002
Posts: 1,365
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From: Huntsville AL
Re: Spark plug wire problem? (JAKE)
Plug gaps wouldn't make it run that badly.
My guess is you got a wire swapped. That will make it run like poopy. Also, you could have cracked and insulator but again, I wouldn't think it would run that bad, especially wanting to die at idle.
Really sounds like one or more wires is on the wrong plug.
My guess is you got a wire swapped. That will make it run like poopy. Also, you could have cracked and insulator but again, I wouldn't think it would run that bad, especially wanting to die at idle.
Really sounds like one or more wires is on the wrong plug.
Race Director
Joined: Feb 2003
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From: Kingman AZ
Cruise-In VII Veteran
Cruise-In VIII
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Re: Spark plug wire problem? (Lord Odin)
I had to do a complete cam change as a local "expert" told me I had adjusted one valve too tight after my engine rebuild. He told me that I had "worn a lobe down" and needed a new cam and lifters! So I pulled the cam and put in the new one along with the new lifters. I then pulled the plugs so I could turn the engine over easier for the valve adjustment process and WTF - one of the
plug gaps was completely closed - thus the crappy idle! I must have bumped the plug or dropped it. So much for listening for a danm Chrysler mechanic!! :boxing
plug gaps was completely closed - thus the crappy idle! I must have bumped the plug or dropped it. So much for listening for a danm Chrysler mechanic!! :boxing
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 3,615
Likes: 1
From: New Lenox IL
Re: Spark plug wire problem? (corvetteronw)
Damn, I'm even getting popping sounds. I had one of my roommates give it a little gas while I listened to the exhaust and its popping. You can notice it more on the low end but its all throughout the power band.
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Drifting
Joined: Feb 2003
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From: Beavercreek OR
Re: Spark plug wire problem? (REDC4CORVETTE)
Firing order for lt1 1 8 4 3 6 5 7 2
drivers side from front of car is 1 3 5 7
Pass side of car front head light 2 4 6 8
:smash:
drivers side from front of car is 1 3 5 7
Pass side of car front head light 2 4 6 8
:smash:
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Re: Spark plug wire problem? (HammerDown)
[SNIP]Plug gaps wouldn't make it run that badly.[/SNIP]
As in Corvetteronw's post, a completely closed plug gap will, in effect, have the engine running as if on 7 or fewer cylinders - depending on how many plugs are closed.
On the other end of the spectrum, if the gap(s) are set much too wide, the spark will arc to ground rather than jump the wide gap.
Spark, like water, will seek the path of least resistance which could be one of the runners, the valve cover or exhaust manifold/header, etc. Wide gaps increase the resistance dramatically and the spark will try to find a way to ground if it can, rather that jump the wide gap.
Jake
As in Corvetteronw's post, a completely closed plug gap will, in effect, have the engine running as if on 7 or fewer cylinders - depending on how many plugs are closed.
On the other end of the spectrum, if the gap(s) are set much too wide, the spark will arc to ground rather than jump the wide gap.
Spark, like water, will seek the path of least resistance which could be one of the runners, the valve cover or exhaust manifold/header, etc. Wide gaps increase the resistance dramatically and the spark will try to find a way to ground if it can, rather that jump the wide gap.
Jake
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 3,615
Likes: 1
From: New Lenox IL
Re: Spark plug wire problem? (JAKE)
I checked the wires and the passenger side is fine. That only leaves two wire possibilities that could have gotten switched. That would be wires 5 and 7 on the plugs. I never touch the wires on the opti. I'll give that a try when the car cools down.
How in the world can I check the firing order? :confused:
How in the world can I check the firing order? :confused:
Melting Slicks
Joined: Apr 2000
Posts: 3,198
Likes: 2
From: Northern CA
Re: Spark plug wire problem? (Lord Odin)
The wires should be fine on the opti end. I posted that so you would know which wire went to which cylinder. The firing order is not of any importance to you at this point. I'm guessing you have aftermarket wires because the stock ones have the numbers printed on the insulation.
If the wires are ok, I would suspect the plugs. If you dropped one during installation, it becomes questionable. Good luck.
If the wires are ok, I would suspect the plugs. If you dropped one during installation, it becomes questionable. Good luck.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Re: Spark plug wire problem? (JasonL)
[SNIP].If the wires are ok, I would suspect the plugs. If you dropped one during installation, it becomes questionable. Good luck.[/SNIP]
Yep, this just happened to another Forum member.
Jake
Yep, this just happened to another Forum member.
Jake
Safety Car
Joined: Jun 1999
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Spark plug wire problem? (Lord Odin)
The cylinder(s) not firing will remain cold. Touch the exhaust manifold by each cylinder to see which one is cold thus not firing.
Also, start the engine in a completely dark garage (at night would be best) and look for leaks from the wires/spark plugs to ground. You will have to let your eyes get adjusted to the dark. It takes about 5 minutes. This is absolutely amazing because you will see a carona around the wires, which is normal, then lots of small sparks coming out of the wires. Be careful of the spinning belts and pulleys.
Also, start the engine in a completely dark garage (at night would be best) and look for leaks from the wires/spark plugs to ground. You will have to let your eyes get adjusted to the dark. It takes about 5 minutes. This is absolutely amazing because you will see a carona around the wires, which is normal, then lots of small sparks coming out of the wires. Be careful of the spinning belts and pulleys.